Plasma coagulation factor ⅩⅢ(pFⅩⅢ)strengthens and stabilizes thrombus mainly by link-ing fibrin molecules and recruiting α2 antiplasmi-nase.Deficiency of this factor causes bleeding char-acterized by"late onset"and spontaneous abor-tion.According to the pathogenesis,it can be divid-ed into two types:congenital and acquired.Ac-quired FⅩⅢ deficiency,which is rare and not easy to identify early,can be caused by an acquired factor inhibitor or by a disease that results in reduced FⅩⅢsynthesis or increased consumption.The most com-mon clinical manifestation is soft tissue hematoma,which occurs in more than 70%of patients,and central nervous system bleeding is also relatively common.With the increasing number of patients with acquired FⅩⅢ deficiency reported,attention has been gradually drawn,but it is still easy to miss and delay diagnosis.This paper reviews the re-search progress on the mechanism,diagnosis and treatment of acquired FⅩⅢ deficiency.